I. Sea Sponges. Plant or Animal?
A. Sea Sponges are animals.
1. Sponges do not have eyes, ears, brains, arms, legs, nerves, muscles or organs!
2. “Sea Sponges are the simplest of multi-cellular organisms (Sponges/ Ocean of Hope).” B. The oldest fossils on the planet are sponges.
1. Sea Sponges have been in the ocean for 600 million years
BODY
I. Sponge’s belong to the scientific classification “Porifera,” which literally means “pore-bearing,” and refers to the many tiny holes on all sponges.
A. Sponges grow in all different shapes, sizes, colors, and textures.
B. “There are about 5,000 species of sea sponges worldwide (Sponges/ Ocean of Hope).”
C. Only about 150 of sponges are found in freshwater lakes and rivers
II. Types of Sponges
A. Sponges are classified within four different classes:
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Calcareous sponge’s skeleton is made of calcareous, star shaped structures or spicules. These usually have three points, but some species have two or four pointed spicules.
C. Glass sponges (class Hexactinellida) are found deep in the ocean. Their tissues contain glass-like structural particles made of silica.
D. The Demospongia is by far the most diverse sponge group.
1. “Greater than 90 percent of the 5,000 known living sponge species are demosponges (Demospongia).”
2. Demosponge skeletons are composed of spongin fibers.
3. The freshwater sponges (family Spongillidae) belong to this class. The common bath sponges, and most of the other sponges used commercially belong to this class.
E. Encrusting sponges have amorphous bodies. They cling to surfaces like rock forming a carpetlike layer over them, spreading much like moss over surfaces on the ocean floor.
(Transition: Visual aid. Example of Barrel Sponge, Toxic Finger Sponge, Elephant Gun, Vase Sponge, and Tube Sponges.}
III. Sponges are amazing filters
A. Sea Sponges have pores that draw in water through their body to their central cavity.
B. The cavity is lined with collar cells which collect the